Such genetic baggage posed safety concerns for potential therapies like cell transplants, and confounded work in the lab, as the introduced genes sometimes spurred mutations that interfered with the normal function of induced cells.

Stem cells produced with no viral remnants

Now, by using a plasmid rather than a virus, James Thompson and Junying Yu have converted adult skin cells into pluripotent stems cells that are completely free of vector and transgene sequences.

The resulting cells, says Thomson, are remarkably similar to embryonic stem cells and show the same capacity to proliferate indefinitely in culture and diversify into all the cell types of the human body. Univ of Wisconsin News

Stem cells for tissue regeneration coming soon

This is a major advance toward safely reprogramming cells for clinical use. The new viral vector-free iPS cells will be available to researchers almost immediately through the International Stem Cell Bank at the WiCell Research Institute.